Trapped with this trapezium

In a trapezium ABCD, if AB||CD then AC² + BD² = BC² + AB² + 2ABCD

How?

Last edited by Agnishom (2013-01-19 16:48:11)

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: Trapped with this trapezium

hi Agnishom,

I haven't fully explored this yet; maybe later; but it has the look of several applications of the cosine rule. As no cos(X) terms exist they must be cancelling out. Remember that angle ABD = angle BDC because of the parallels.

Re: Trapped with this trapezium

Let me check....

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: Trapped with this trapezium

Sorry, it should have been AC² + BD² = BC² + AD² + 2ABCD

P.S.: I have a hint in my book. But I dont get it. Do you want it?

Last edited by Agnishom (2013-01-20 01:08:14)

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: Trapped with this trapezium

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: Trapped with this trapezium

Re: Trapped with this trapezium

Got it .... Thanks

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.